1. Field of the Invention
The present invention relates to an image forming apparatus and more particularly to an image forming apparatus of the type operable in a duplex print mode and capable of stacking prints face down in order of page.
2. Description of the Background Art
An electrophotographic copier, printer, facsimile apparatus or similar image forming apparatus of the type described usually includes a first path and a second path arranged at the sheet discharge side of an image forming section 102. The first path conveys a sheet carrying an image thereon toward a sheet outlet section while the second path conveys it in a duplex print mode or to reverse the sheet and then discharge it. A path selector is located at the position where the first and second paths part from each other. The path selector selectively steers a sheet coming out of the image forming section to the first path or the second path.
The second path merges into a switchback path that reverses the sheet by switching it back. A reverse roller is positioned on the switchback pack and movable into and out of contact with the sheet (up-and-down direction). In the duplex print mode, the refeed path again conveys the sheet switched back by the switchback path toward the image forming section. The reverse discharge path discharges the above sheet to a sheet outlet section face down in order of page. The refeed path is positioned below the switchback path. A path selector is located at a position where the refeed path and reverse discharge path part from each other. This path selector selectively steers the sheet switched back by the switchback path to the refeed path or the reverse discharge path.
To reverse the sheet carrying an image on one side thereof and then discharge it, the path selector again delivers the sheet to the second path. In this case, the path selector is so positioned as to steer the sheet driven out of the switchback path to the reverse discharge path. As a result, the sheet is driven out to the sheet outlet section face down via the reverse discharge path.
The conventional image forming apparatus described above has undesirably great height because of the switch back path and refeed path arranged one above the other.
Technologies relating to the present invention are disclosed in, e.g., Japanese Patent Laid-Open Publication No. 6-236086 and Japanese Patent No. 2,941,021.
It is an object of the present invention to provide an image forming apparatus capable of enhancing the productivity of image formation in a repeat print mode by reducing the interval between consecutive sheets at an image forming section, and obviating the need for an exclusive switchback path for a duplex print mode.
An image forming apparatus of the present invention includes a sheet tray loaded with a stack of sheets. A separating and feeding device feeds one sheet from the sheet tray while separating it from the other sheets. An image forming section forms an image on the sheet fed by the separating and feeding device. A conveyance path conveys the sheet from the sheet tray to the image forming section. A switchback path is connected to the intermediate portion of the conveyance path for receiving the sheet being conveyed along the conveyance path. A reversing device is selectively switchable to a first position for switching back the preceding sheet introduced into the switchback path to thereby feed it to the conveyance path or a second position for allowing the preceding sheet being fed from the switchback path and the following sheet to be introduced into the switchback path after the preceding sheet to at least partly overlap each other. A refeed path is connected to the sheet outlet side of the image forming section and part of the conveyance path upstream of the switchback path. A conveying device conveys the sheet driven into the refeed path to the conveyance path.